in which the Cotton tensor takes the form [1]}
\(\mathfrak {C}_{\alpha (2s)}(h)&=&\Box ^{s-1}\partial ^{\beta }{}_{(\alpha _1}h_{\alpha _2\dots \alpha _{2s})\beta }=\Box ^{s-1}\partial ^{\beta }{}_{\alpha _1}h_{\alpha _2\dots \alpha _{2s}\beta }~,\\\mathfrak {C}_{\alpha (2s+1)}(h)&=&\Box ^s h_{\alpha (2s+1)}~.\) 
